/*
提交链接:https://leetcode.cn/problems/maximize-palindrome-length-from-subsequences/description/
1771. [由子序列构造的最长回文串的长度 2182]
赖德檀 2024/10/23
*/
  
class Solution {
public:
    int longestPalindrome(string word1, string word2) {
        string s=word1+word2;
        int n=s.size();
        int m=word1.size();
        int ans=0;
        vector<vector<int>>dp(n,vector<int>(n,0));
        for(int i=0;i<n;i++)
        dp[i][i]=1;
        for(int i=n-1;i>=0;i--)
        {
            for(int j=i+1;j<n;j++)
            {
                if(s[i]==s[j])
                {
                    dp[i][j]=dp[i+1][j-1]+2;
                }
                else
                dp[i][j]=max(dp[i+1][j],dp[i][j-1]);
                if(s[i]==s[j]&&i<m&&j>=m) //避免全选words1/words2
                ans=max(ans,dp[i][j]);
            }
        }
        return ans;
    }
};